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Map IPv{4,6} addresses to ethernet addresses

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...in accordance with RFCs 1112 and 2464.

Fixes IPv4 multicast when IP_MULTICAST_IF is specified.

Don't return ErrNoRoute when no route is needed.
Don't set Route.NextHop when no route is needed.

PiperOrigin-RevId: 236199813
Change-Id: I48ed33e1b7f760deaa37e18ad7f1b8b62819ab43
This commit is contained in:
Tamir Duberstein
2019-02-28 14:38:32 -08:00
committed by Shentubot
parent 05d721f9ee
commit 3830786883
4 changed files with 76 additions and 45 deletions
Download Patch File Download Diff File Expand all files Collapse all files
pkg/tcpip/network/arp/arp.go
+19 -1
View File
@@ -160,9 +160,27 @@ func (*protocol) LinkAddressRequest(addr, localAddr tcpip.Address, linkEP stack.
// ResolveStaticAddress implements stack.LinkAddressResolver.
func (*protocol) ResolveStaticAddress(addr tcpip.Address) (tcpip.LinkAddress, bool) {
if addr == "\xff\xff\xff\xff" {
if addr == header.IPv4Broadcast {
return broadcastMAC, true
}
if header.IsV4MulticastAddress(addr) {
// RFC 1112 Host Extensions for IP Multicasting
//
// 6.4. Extensions to an Ethernet Local Network Module:
//
// An IP host group address is mapped to an Ethernet multicast
// address by placing the low-order 23-bits of the IP address
// into the low-order 23 bits of the Ethernet multicast address
// 01-00-5E-00-00-00 (hex).
return tcpip.LinkAddress([]byte{
0x01,
0x00,
0x5e,
addr[header.IPv4AddressSize-3] & 0x7f,
addr[header.IPv4AddressSize-2],
addr[header.IPv4AddressSize-1],
}), true
}
return "", false
}
pkg/tcpip/network/ipv6/icmp.go
+19
View File
@@ -206,6 +206,25 @@ func (*protocol) LinkAddressRequest(addr, localAddr tcpip.Address, linkEP stack.
// ResolveStaticAddress implements stack.LinkAddressResolver.
func (*protocol) ResolveStaticAddress(addr tcpip.Address) (tcpip.LinkAddress, bool) {
if header.IsV6MulticastAddress(addr) {
// RFC 2464 Transmission of IPv6 Packets over Ethernet Networks
//
// 7. Address Mapping -- Multicast
//
// An IPv6 packet with a multicast destination address DST,
// consisting of the sixteen octets DST[1] through DST[16], is
// transmitted to the Ethernet multicast address whose first
// two octets are the value 3333 hexadecimal and whose last
// four octets are the last four octets of DST.
return tcpip.LinkAddress([]byte{
0x33,
0x33,
addr[header.IPv6AddressSize-4],
addr[header.IPv6AddressSize-3],
addr[header.IPv6AddressSize-2],
addr[header.IPv6AddressSize-1],
}), true
}
return "", false
}
pkg/tcpip/stack/stack.go
+24 -34
View File
@@ -752,49 +752,39 @@ func (s *Stack) FindRoute(id tcpip.NICID, localAddr, remoteAddr tcpip.Address, n
s.mu.RLock()
defer s.mu.RUnlock()
// We don't require a route in the table to send a broadcast, multicast or
// IPv6 link-local packet out on a NIC.
isBroadcast := remoteAddr == header.IPv4Broadcast
isMulticast := header.IsV4MulticastAddress(remoteAddr) || header.IsV6MulticastAddress(remoteAddr)
if id != 0 && (isBroadcast || isMulticast || header.IsV6LinkLocalAddress(remoteAddr)) {
needRoute := !(isBroadcast || isMulticast || header.IsV6LinkLocalAddress(remoteAddr))
if id != 0 && !needRoute {
if nic, ok := s.nics[id]; ok {
if ref := s.getRefEP(nic, localAddr, netProto); ref != nil {
return makeRoute(netProto, ref.ep.ID().LocalAddress, remoteAddr, nic.linkEP.LinkAddress(), ref), nil
}
}
return Route{}, tcpip.ErrNoRoute
} else {
for _, route := range s.routeTable {
if (id != 0 && id != route.NIC) || (len(remoteAddr) != 0 && !route.Match(remoteAddr)) {
continue
}
if nic, ok := s.nics[route.NIC]; ok {
if ref := s.getRefEP(nic, localAddr, netProto); ref != nil {
if len(remoteAddr) == 0 {
// If no remote address was provided, then the route
// provided will refer to the link local address.
remoteAddr = ref.ep.ID().LocalAddress
}
r := makeRoute(netProto, ref.ep.ID().LocalAddress, remoteAddr, nic.linkEP.LinkAddress(), ref)
if needRoute {
r.NextHop = route.Gateway
}
return r, nil
}
}
}
}
// TODO: Route multicast packets with no specified local
// address or NIC.
for i := range s.routeTable {
if (id != 0 && id != s.routeTable[i].NIC) || (len(remoteAddr) != 0 && !s.routeTable[i].Match(remoteAddr)) {
continue
}
nic := s.nics[s.routeTable[i].NIC]
if nic == nil {
continue
}
ref := s.getRefEP(nic, localAddr, netProto)
if ref == nil {
continue
}
if len(remoteAddr) == 0 {
// If no remote address was provided, then the route
// provided will refer to the link local address.
remoteAddr = ref.ep.ID().LocalAddress
}
r := makeRoute(netProto, ref.ep.ID().LocalAddress, remoteAddr, nic.linkEP.LinkAddress(), ref)
r.NextHop = s.routeTable[i].Gateway
return r, nil
}
if isMulticast {
if !needRoute {
return Route{}, tcpip.ErrNetworkUnreachable
}
pkg/tcpip/stack/stack_test.go
+14 -10
View File
@@ -654,8 +654,8 @@ func TestBroadcastNeedsNoRoute(t *testing.T) {
s.SetRouteTable([]tcpip.Route{})
// If there is no endpoint, it won't work.
if _, err := s.FindRoute(1, header.IPv4Any, header.IPv4Broadcast, fakeNetNumber); err != tcpip.ErrNoRoute {
t.Fatalf("got FindRoute(1, %v, %v, %v) = %v, want = %v", header.IPv4Any, header.IPv4Broadcast, fakeNetNumber, err, tcpip.ErrNoRoute)
if _, err := s.FindRoute(1, header.IPv4Any, header.IPv4Broadcast, fakeNetNumber); err != tcpip.ErrNetworkUnreachable {
t.Fatalf("got FindRoute(1, %v, %v, %v) = %v, want = %v", header.IPv4Any, header.IPv4Broadcast, fakeNetNumber, err, tcpip.ErrNetworkUnreachable)
}
if err := s.AddAddress(1, fakeNetNumber, header.IPv4Any); err != nil {
@@ -675,8 +675,8 @@ func TestBroadcastNeedsNoRoute(t *testing.T) {
}
// If the NIC doesn't exist, it won't work.
if _, err := s.FindRoute(2, header.IPv4Any, header.IPv4Broadcast, fakeNetNumber); err != tcpip.ErrNoRoute {
t.Fatalf("got FindRoute(2, %v, %v, %v) = %v want = %v", header.IPv4Any, header.IPv4Broadcast, fakeNetNumber, err, tcpip.ErrNoRoute)
if _, err := s.FindRoute(2, header.IPv4Any, header.IPv4Broadcast, fakeNetNumber); err != tcpip.ErrNetworkUnreachable {
t.Fatalf("got FindRoute(2, %v, %v, %v) = %v want = %v", header.IPv4Any, header.IPv4Broadcast, fakeNetNumber, err, tcpip.ErrNetworkUnreachable)
}
}
@@ -732,17 +732,21 @@ func TestMulticastOrIPv6LinkLocalNeedsNoRoute(t *testing.T) {
anyAddr = header.IPv6Any
}
want := tcpip.ErrNetworkUnreachable
if tc.routeNeeded {
want = tcpip.ErrNoRoute
}
// If there is no endpoint, it won't work.
if _, err := s.FindRoute(1, anyAddr, tc.address, fakeNetNumber); err != tcpip.ErrNoRoute {
t.Fatalf("got FindRoute(1, %v, %v, %v) = %v, want = %v", anyAddr, tc.address, fakeNetNumber, err, tcpip.ErrNoRoute)
if _, err := s.FindRoute(1, anyAddr, tc.address, fakeNetNumber); err != want {
t.Fatalf("got FindRoute(1, %v, %v, %v) = %v, want = %v", anyAddr, tc.address, fakeNetNumber, err, want)
}
if err := s.AddAddress(1, fakeNetNumber, anyAddr); err != nil {
t.Fatalf("AddAddress(%v, %v) failed: %v", fakeNetNumber, anyAddr, err)
}
r, err := s.FindRoute(1, anyAddr, tc.address, fakeNetNumber)
if tc.routeNeeded {
if r, err := s.FindRoute(1, anyAddr, tc.address, fakeNetNumber); tc.routeNeeded {
// Route table is empty but we need a route, this should cause an error.
if err != tcpip.ErrNoRoute {
t.Fatalf("got FindRoute(1, %v, %v, %v) = %v, want = %v", anyAddr, tc.address, fakeNetNumber, err, tcpip.ErrNoRoute)
@@ -759,8 +763,8 @@ func TestMulticastOrIPv6LinkLocalNeedsNoRoute(t *testing.T) {
}
}
// If the NIC doesn't exist, it won't work.
if _, err := s.FindRoute(2, anyAddr, tc.address, fakeNetNumber); err != tcpip.ErrNoRoute {
t.Fatalf("got FindRoute(2, %v, %v, %v) = %v want = %v", anyAddr, tc.address, fakeNetNumber, err, tcpip.ErrNoRoute)
if _, err := s.FindRoute(2, anyAddr, tc.address, fakeNetNumber); err != want {
t.Fatalf("got FindRoute(2, %v, %v, %v) = %v want = %v", anyAddr, tc.address, fakeNetNumber, err, want)
}
})
}